4 color process printing involves the use of four plates: Cyan, Magenta, Yellow and Keyline (Black). The CMYK artwork (which you will have supplied) is separated into these four colors – one plate per color. The four CMYK inks are applied one by one to four different rollers and the paper or label stock is then fed through the printing press. The colors are applied to the stock one by one and out comes the full color (4 color process) result.
8 color spot printing creates brighter, more vibrant results with a smaller color range. When printing in single (spot) colors, a single color ink (normally with a Pantone reference number) is applied to the printing press roller. If there is just one color to be printed, there will be a single plate and a single run of the press. If there are two colors, there will be two plates and so on. The colors are layered onto the paper one by one.